Piezoelectric properties of zinc blende quantum dots

Piezoelectric coefficients of zinc blende (ZB) InN, GaN, and AlN have been estimated from the piezoelectric coefficients of the wurtzite (WZ) system. This procedure is based on a rotation of the first-order piezoelectric tensor of a (001)-oriented ZB structure to a (111)-oriented ZB structure, which is similar to a WZ structure. The derived expressions for the piezoelectric coefficients in a (111)-oriented ZB system are benchmarked against literature coefficients of different WZ materials, showing a very good agreement. To perform the desired opposite operation, a least square fitting procedure was used to find the ZB piezoelectric coefficient e₁₄ that provides the closest reverse transformation to the known WZ constants. Using e₁₄, the piezoelectric potential in a GaN/AlN QD is calculated and compared to a InAs/GaAs QD, revealing a much larger potential in the nitride system, even though the lattice mismatch is much smaller in this system. The result is related to the large piezoelectric coefficient e₁₄ in ZB nitride materials.